目瞪口呆
mù dèng koǔ dāi · HSK 7
dumbstruck
😦 目 eyes + 瞪 stare + 口 mouth + 呆 blank = eyes staring, mouth gaping = dumbstruck
瞪 — eye 目 + ascend 登 (phonetic)
瞪 is a semantic-phonetic compound: 目 ('eye') gives the meaning, while 登 ('to ascend') supplies the sound. It originally referred to opening the eyes wide, and came to mean staring or glaring at someone, often with surprise or anger.
口 — pictograph of an open mouth
口 is one of the oldest pictographs in Chinese, originally drawn as a simple outline of an open mouth. Its core meaning 'mouth' extended naturally to 'opening' or 'entrance', as in 入口 (entrance). It also serves as a common radical in characters related to speech, eating, or apertures.
呆 — mouth 口 + tree/wood 木
Originally a variant of 保 (to protect), depicting a person carrying a child. Over time the form simplified to 口 over 木 and the meaning shifted to 'dull, foolish, stunned.' Today 呆 mainly means dumbstruck or slow-witted, as in 发呆 (to space out).